#1: Blastin' And Relaxin': Kill 180 enemies in any game mode in Reach (2000 cR)
#2: Covenant-Cide: Kill 90 enemies in Firefight Matchmaking (1000 cR)
#3: Five-Time Champ: Win 5 games in multiplayer Matchmaking (750 cR)
#4: Oops! All Kills: Earn 5 multikils in multiplayer Matchmaking (400 cR)
Total: 4150 Points
Ehh, not a lot of points today, but luckily they're mostly multiplayer Matchmaking, so you'll be able to progress though the weekly challenge in the meantime. Blastin' And Relaxin' is nothing new, and neither is Covenant-Cide (just play Rocketfight). Five-Time Champ is most easily accomplished on Team games and shouldn't be that hard since it's not "in a row" or anything like that. Oops! All Kills you should probably try in the game mode your best at, since any will do as long as you can kill a lot of people. Be careful of Armor Lock though with this challenge, since you could be standing there waiting for it to dry up and another guy just comes up and beats the shit out of you.